The present invention relates to a communication system for electronic messages and in particular relates to a communication system for transmitting electronic messages and electronic mail, respectively, between data processing devices, connected to each other via a communication network.
The importance of transmitting messages by using electronic means is steadily growing. Particularly with the introduction of personal computers, the exchange of information using computer aided systems is not limited any longer to a relatively small group having access to networks of computers, e.g., in research and development facilities, but is accessible by broader parts of the population.
In a system for exchanging information with a plurality of computers, interconnected by a network, electronic messages (electronic mail) can be transmitted via the network from any one computer to any other computer. It is, however, required that all computers that are part of the data communication or transmission of an electronic message agree upon a uniform method and data format for exchanging message data, as for example the address of the recipient or for specifying the partition of the electronic mail containing the actual message, only if the same method is applied for generating an electronic message, as well as for analyzing an electronic message, is a meaningful interpretation of data transmitted from one computer to one or more other computers possible.
In this connection, methods for communication and communications protocols for the exchange of electronic messages between computers via a computer network were developed. These methods enable the user of a first computer to generate a message containing, e.g., plain text and, after specifying a recipients address, to transmit the message as an electronic message to a second computer. The second computer receives the electronic message and stores it or reproduces it, respectively. It is also possible to store the message at a suitable location in the network and to actively retrieve it later using a computer.
Some of these methods are widely used and accepted. Most importantly, with the introduction of the Internet, a world wide network of computers, methods and standards have been developed for transmitting mostly text as an electronic message or electronic mail, a so called email. The MIME "Multi-Purpose Internet Mail Extensions" Standard by Borenstein and N. Freed (RFC 1521, September 1993) defines one of these methods for exchanging electronic messages between data processing devices. This standard is widely used for Internet applications.
A message exchanged between computers according to one of these methods, e.g. according to the MIME standard, may have the following structure: A first partition of the data set to be transmitted contains information concerning the method which was employed for creating the electronic message, in order to enable the receiving data processing device to choose a suitable program for interpreting or analyzing the received electronic message. In a second partition of the data set which is to be transmitted, the type of the message or a format of the data of the actual message is specified. For example, data constituting a message may be coded or may be transformed in a particular manner, and thus the second data field enables the receiving data processing device to suitably retransform the message in order to meaningfully represent it. In a third partition of the data set constituting the electronic message, the actual message is contained in the format described in the second partition of the data set.
The transmission of an electronic message according to this method could happen in the following way: In a first step, e.g. using a data processing device, a piece of electronic text is created, which is to be transmitted to a recipient. The mailer may be advised by a processing command to provide the necessary information for creating the electronic mail "email". For example, the address of the recipient, an Internet address, would be requested as an integral part of the electronic message. In addition, further information can optionally be provided, e.g. distribution, coding and the like. In a second step, the mailer instructs the data processing device to mail the electronic message over the network. Subsequently the message is delivered to a receiving data processing device, specified by the address. If a recipient desires to view received mail, he activates a program at a data processing device, which displays the received electronic message in accordance with the data partitions described above. Various further functions, such as replying, forwarding and storing of the electronic message, are possible.
Some methods for exchanging electronic messages between data processing devices do not only enable the transmission of text as an electronic message but also enable the transmission of other media. For example, the above mentioned MIME standard allows to transmit, besides text information, image data, audio data, video data and data regarding certain applications and application programs, respectively. Thus a partition of the data of the electronic message could be reserved for text data, another partition for image data, and similarly further partitions for video, audio and the like.
FIG. 5 shows an example of the structure of an electronic message B, that could be displayed on a display (not shown) by a receiving data processing device D. A data segment B1 contains address information, e.g., specifying the Internet address of the sending station and the Internet address of the recipient. A data segment B2 of the email displays a text block containing a written message, a segment B3 displays an image, a segment B4 of the display contains information indicating video data, which can be played back following a selection using a selection device, e.g. a cursor and by clicking a mouse button. Similarly section B5 contains information indicating audio data, which can be played back using the selection means of the data processing device.
In the communication system with the above described method, an electronic message is interpreted by the receiving data processing device and data segments of particular data blocks or media are displayed on the display, played back, stored and the like. However, it is possible, that certain relations between the data sections B1 to B5 were of importance while creating the message. For example, an electronic message could contain a text block, wherein specific passages of the text block in content relate to another specific passage, a picture or the like.
In the above described communication system, it is a disadvantage, that there is no easy way of including those relations into the electronic message for transmitting it to a recipient.